234k views
0 votes
In the chemical formula H₂O, what does the subscript 2 represent?

a) Number of hydrogen atoms
b) Number of oxygen atoms
c) Number of water molecules
d) Molecular weight of water

User Zhuoying
by
8.3k points

1 Answer

6 votes

Final answer:

In the chemical formula H₂O, the subscript '2' means there are two hydrogen atoms in one molecule of water.

Step-by-step explanation:

In the chemical formula H₂O, the subscript '2' represents the number of hydrogen atoms in one molecule of water. Therefore, the correct answer is: a) Number of hydrogen atoms. This subscript indicates that there are two hydrogen atoms bonded to one oxygen atom within a single molecule of water. In contrast, if there were a coefficient before the formula, such as 2H₂O, this would indicate two separate water molecules, each still with two hydrogen and one oxygen atom.

It's crucial to differentiate between subscripts and coefficients in chemical formulas. A subscript applies to the atom it's attached to and tells us the number of those atoms in one molecule, whereas a coefficient applies to the entire formula and indicates how many of those molecules there are. Therefore, we cannot simply change the subscripts in a molecular formula, as this would represent a different compound. For example, changing the formula of water (H₂O) to include a subscript of 2 on the oxygen (making it H₂O₂) would change the compound from water to hydrogen peroxide, which has very different properties.

User Brianyang
by
8.1k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.